Factor download functionality out of export()
This way any kind of data can be offered as downloadable file.
Patch by: Sverre Rabbelier
from django.contrib import admin
from django.contrib.sites.models import Site
class SiteAdmin(admin.ModelAdmin):
list_display = ('domain', 'name')
search_fields = ('domain', 'name')
admin.site.register(Site, SiteAdmin)